Gear mechanism



Jan. 21, 1936.. R. J. l.. MOINEAU GEAR MECHANISM Filed March 24, 193313:: hLavI-S Mohaa-J Rene 5e? NVEN-TOK 4Patented Jan. 2l, 1936 vPATENTlowner;

A GEAR MEcHANIsM 1 ,I

Ren Joseph Louis Moineau, Paris, France Applicationr March 24, 1933,Serial No. 662.4.83 v In France April 29, 1932 i 5 claims. (ci. 10a-117) Thepresent invention relates to improvements in gear mechanisms andchiefly in those which yare adapted to be used as pumps, motors, com- Apressors, etc.

In conformity to the invention, one at least of the elements forming themechanism is wholly or partially elastic, yielding, or adapted toreceive a slight dispacement, in order to assure .the

contact between all of the gear elements without appreciable vplay andupon a great length.

The invention is chiefly applicable to mechanisms provided with helicalgearings, and comprising a female element and one or moremale elementsdisposed and movable within said female element and which are constantlyin contact with this latter element in any cross section thereof. In oneform of construction, one or all of the elements of a mechanismaccording tothe invention consist of an elastic substance such as Indiarubber, leather, wood or the like, whose dimensions are such as toassure the pressure of one of .the said elements with respect to theother.

AOther forms of construction will be set forth in the followingdescription.

In the accompanying drawing, which is given solely by way of example:

Fig. l is a lengthwise section of an apparatus provided with helicalgearing elements improved according to the invention.

Fig. 2 is a partial horizontal section on the line 2--2 of Fig. 1.

.to 3, the apparatus comprises a stationary element I containing arotary part 2. These two parts I and 2 have a helical form. lThe elementI has for instance two helical threads or teeth,

whilst the rotary part 2 is provided with one,

thread which in each cross-section of the device is constantly incontact with the surface of the outer element I.

The pitch of the threads of the parts I and 2 may be constant or not.These pitches, flor each section, will depend upon the number of teeth.

In conformity to the invention, the outer part I consists of an elasticsubstance such as India rubber, leather or'the like. It is held in placeby a cylindrical metallic member 3.

Owing to the elasticity of the part I, all play is practically avoidedupon a great length of the line of contact between the parts I and 2;and 5 this absence of play will be obviously furthered if the inner part2 is movable in the outer part I without any guiding means. The part 24maybe rotated, as herein represented'by a small flexible member 4,which may if necessary be replaced l0 by a small double-cardan shaft.

Two end-pieces 5-6, whichA are provided with respective necks 1 8, areconnected together by bolts 9 and' support the member 3 and the part I.The end-piece 6 is tted with a stumng-box 15 I0 which is pressed byscrews I I, and thus the saidstuillng-box separates the bearing I2 ofthe device which may act as a pump, permitting thus a supply oflubricant at I3.l

The operation of the pump is the following: 23 Between the two male andfemale elements are formed suitable closed spaces due to the differenceof the numbers ofthreads on each element. The number of these spacesdepends obviouslyy upon the number of threads provided on these 25gearlelements. When one of the gear elements is rotated with respect tothe other the said spaces between the elements are displaced in alongitudinal direction and it is evident that if a ensure a perfecttightness between the different parts of the gear elements and a correct35 functioning of the mechanisms.

It will be observed that al1 of the above mentioned pieces can bemoulded or cast.

' In the present construction, the outer part has a length whichmisequal to one pitch, but it may 40 also have a length equal to severalpitches. Portions of elements with reversed pitches may beplaced-end-to-end in order to overcome the. axial thrust.

'I'he internal part 2 may also be made elastic, 45 and in this case theouter part I may be elastic or not. y

The elasticityof the internal part 2 may be obtained by constructing itwith an elastic inaterial, or in any other suitable manner.

In the case the cross-section of the internal part 2 of the device beingconstantly circular, the elasticity may be obtained by providing theinternal part 2a with circular packing rings Il (Fig. 4) which areoptionallysplit, are very thin, 55

and are in close contact; or further, by surrounding the said part orcore 2a by a wire I 5 (Fig. or the like, which is wound in a spiralabout the said core.

In this case, the diameter of the rings I4 or oi' the turns of wire I5should somewhat exceed the diameter of the cross-section o! the part I,in order that a suitable contact may be assured by the yielding of therings or thev wire spires.

It is evident that such rings Il or wire I5 may be employed inconjunctionl with the tlrstmentioned arrangement, by rendering the core2a of part 2 elastic.

In another arrangement, the internal part 2 is constructed by means of acore 2a upon which is mounted a set of thin circular discs I1' (Figs. 6and 7) each of which may be displaced as shown in Fig. 7, thus tendingto move away trom the axis either by the action of a spring, or bycentrifugal force. The discs I1 may also be split in order to exertpressure by the increase of their diameter. Thisl latter arrangement mayeven be employed alone, as shown in Fig. 8.

The part 2 may be further constructed by means of a core 2a, Figs. 6 and"I, upon which is pressed a set of circular textile pieces, the rigidityof which will be assured by centrifugal force.

Whatever be the construction adapted, the part 2 will be preferablygiven a density which is practically equal to the density of the uid, inorder to obtain a perfect equilibrium. The part 2 will then be enabledto float in the fluid.

It is evident that the principle of the invention is further applicableyto mechanisms with ordinary gearings, of all kinds.

Obviously, the said invention is not limited to the forms ofconstruction herein described and represented, which are given solely byway of example.

Having now described my invention what I claim as'new and desire tosecure by Letters Patent is:

1. A gear mechanism adapted for use as a pump, motor or the likecomprising a casing, in-

iet and outlet conduits in said casing. a female helical gear elementinside said casing and a male helical gear element located in thislatter and always in contact therewith in any cross section, the numbero! threads of said female element exceeding by one unit thecorresponding number of threads on the male element and one at least ofsaid elements being deformable, thus ensuring a perfect tightness of thejoints and providing for a closed tight axial space comprised betweensaid male and female elements and wherein the iluid is contained, saidspace communicating with said outlet and inlet conduits, and drivingmeans for the rotation of one of said gear elements.

2. A gear mechanism adapted for the use as a pump, motor or the likecomprising a casing, outlet and inlet conduits in said casing, a femalehelical gear element inside said casing and at least one male helicalgear element disposed within said female element, the number of threadsof the female element exceeding by one unit the corresponding number ofthreads of the male element, one at least of the inner elements beingformed of a core covered by an elastic means, thus ensuring a perfecttightness of the joints and providing for a closed tight axial spacecomprised between said male and female elements and wherein the iiuid iscontained, said space cornmunicating with said outlet and inletconduits, and 'driving means for the rotation of one of said gearelements.

3. A gear mechanism according to claim 1 the inner male helical gearelement having a specific Weight which is substantially equal to that ofthe liquid operated upon by said mechanism.

4. A gear mechanism according to claim 1 further comprising exible meansconnnecting the movable parts oi' said mechanism and said driving means.

5. A gear mechanism according to claim 1 wherein one element at least ismade of India rubber.

REN JOSEPH LOUIS MOINEAU.

